Fix theme lag

StikJIT/Utilities/AppTheme.swift

@@ -130,6 +130,10 @@ struct ThemedBackground: View {
     @Environment(\.accessibilityReduceMotion) private var reduceMotion
     @Environment(\.colorScheme) private var colorScheme
 
+    private var identity: String {
+        style.identityKey
+    }
+
     var body: some View {
         Group {
             switch style {
@@ -166,6 +170,7 @@ struct ThemedBackground: View {
                     .ignoresSafeArea()
             }
         }
+        .id(identity)
     }
 }
 
@@ -329,8 +334,15 @@ private struct ParticleFieldBackground: View {
                     }
                 }
                 .task {
-                    while true {
+                    while !Task.isCancelled {
-                        try? await Task.sleep(nanoseconds: 16_000_000)
+                        do {
+                            try await Task.sleep(nanoseconds: 16_000_000)
+                        } catch is CancellationError {
+                            break
+                        } catch {
+                            break
+                        }
+                        guard !Task.isCancelled else { break }
                         var next = particles
                         for i in next.indices {
                             var p = next[i]
@@ -359,4 +371,37 @@ private extension Array where Element == Color {
         if count == 1 { return [self[0], self[0].opacity(0.6)] }
         return self
     }
+
+    var identityKey: String {
+        map { $0.identityKey }.joined(separator: ",")
+    }
+}
+
+private extension BackgroundStyle {
+    var identityKey: String {
+        switch self {
+        case .staticGradient(let colors):
+            return "static:\(colors.identityKey)"
+        case .animatedGradient(let colors, let speed):
+            return "animated:\(String(format: "%.4f", speed)):\(colors.identityKey)"
+        case .blobs(let colors, let background):
+            return "blobs:\(colors.identityKey)|bg:\(background.identityKey)"
+        case .particles(let particle, let background):
+            return "particles:\(particle.identityKey)|bg:\(background.identityKey)"
+        case .customGradient(let colors):
+            return "custom:\(colors.identityKey)"
+        case .adaptiveGradient(let light, let dark):
+            return "adaptive:l=\(light.identityKey)|d=\(dark.identityKey)"
+        }
+    }
+}
+
+private extension Color {
+    var identityKey: String {
+        if let hex = toHex() {
+            return hex
+        }
+        // Fallback to descriptive string when hex can't be produced (e.g. dynamic colors)
+        return String(describing: self)
+    }
 }

StikJIT/Views/DisplayView.swift

@@ -487,16 +487,17 @@ struct DisplayView: View {
             // Grid of theme previews
             LazyVGrid(columns: [GridItem(.flexible()), GridItem(.flexible())], spacing: 12) {
                 ForEach(AppTheme.allCases, id: \.self) { theme in
+                    let isSelected = selectedBuiltInTheme == theme && selectedCustomTheme == nil
                     ThemePreviewCard(style: theme.backgroundStyle,
                                      title: theme.displayName,
-                                     selected: selectedBuiltInTheme == theme && selectedCustomTheme == nil,
+                                     selected: isSelected,
                                      action: {
                                          guard hasThemeExpansion else { return }
                                          appThemeRaw = theme.rawValue
                                          applyThemePreferences()
                                          showSavedToast()
                                      },
-                                     staticPreview: false)
+                                     staticPreview: !isSelected)
                 }
             }
         }
@@ -582,15 +583,16 @@ struct DisplayView: View {
                     LazyVGrid(columns: [GridItem(.flexible()), GridItem(.flexible())], spacing: 12) {
                         ForEach(manager.customThemes, id: \.id) { theme in
                             let identifier = manager.customThemeIdentifier(for: theme)
+                            let isSelected = selectedCustomTheme?.id == theme.id
                             ThemePreviewCard(style: manager.backgroundStyle(for: identifier),
                                              title: theme.name,
-                                             selected: selectedCustomTheme?.id == theme.id,
+                                             selected: isSelected,
                                              action: {
                                                  appThemeRaw = identifier
                                                  applyThemePreferences()
                                                  showSavedToast()
                                              },
-                                             staticPreview: false)
+                                             staticPreview: !isSelected)
                             .contextMenu {
                                 Button("Edit") { editingCustomTheme = theme }
                                 Button("Delete", role: .destructive) {
@@ -955,4 +957,3 @@ private struct CustomThemeEditorView: View {
         }
     }
 }
-